Improving a control and sequencing language

In a process control environment, batch processes, as opposed to continuous pro­cesses, are characterised by multi-product manufacturing lines producing relatively small quantities which often involves frequent product changes. One component of batch control systems is a programming language which is used to control and syn­chronise the operations of the plant. Initially low-level languages (e.g. ladder logic, boolean algebra and assembly language) were used, but have now been replaced by specialised high-level languages . These languages provide more functionality and are easier to use. This paper examines one such a high-level sequencing language (CASL) and identifies functionality, clarity and readability improvements that can be made to the existing language. An implementation of an upwardly compatible compiler for the improved language is described briefly